.\"	$NetBSD: puffs_cc.3,v 1.14 2009/04/11 16:48:53 wiz Exp $
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.Dd January 28, 2008
.Dt PUFFS_CC 3
.Os
.Sh NAME
.Nm puffs_cc
.Nd puffs continuation routines
.Sh LIBRARY
.Lb libpuffs
.Sh SYNOPSIS
.In puffs.h
.Ft void
.Fn puffs_cc_yield "struct puffs_cc *pcc"
.Ft void
.Fn puffs_cc_continue "struct puffs_cc *pcc"
.Ft void
.Fn puffs_cc_schedule "struct puffs_cc *pcc"
.Ft struct puffs_cc *
.Fn puffs_cc_getcc "struct puffs_usermount *pu"
.Sh DESCRIPTION
These routines are used for the cooperative multitasking suite present
in puffs.
.Pp
.Bl -tag -width xxxx
.It Fn puffs_cc_yield "pcc"
Suspend and save the current execution context and return control
to the previous point.
In practice, from the file system author perspective, control returns
back to where either the mainloop or where
.Fn puffs_dispatch_exec
was called from.
.It Fn puffs_cc_continue pcc
Will suspend current execution and return control to where it was
before before calling
.Fn puffs_cc_yield .
This is rarely called directly but rather through
.Fn puffs_dispatch_exec .
.It Fn puffs_cc_schedule "pcc"
Schedule a continuation.
As opposed to
.Fn puffs_cc_continue
this call returns immediately.
.Fa pcc
will be scheduled sometime in the future.
.It Fn puffs_cc_getcc "pu"
Returns the current pcc or
.Dv NULL
if this is the main thread.
.Em NOTE :
The argument
.Ar pu
will most likely disappear at some point.
.El
.Pp
Before calling
.Fn puffs_cc_yield
a file system will typically want to record some cookie value into its
own internal bookkeeping.
This cookie should be hooked to the
.Va pcc
so that the correct continuation can be continued when the event it
was waiting for triggers.
Alternatively, the
.Xr puffs_framebuf 3
framework and
.Fn puffs_mainloop
can be used for handling this automatically.
.Sh SEE ALSO
.Xr puffs 3 ,
.Xr puffs_framebuf 3
